JP6544485B2 - Ceramic electronic component and method of manufacturing ceramic electronic component - Google Patents

Description

The present invention relates to a ceramic electronic component and a method of manufacturing the ceramic electronic component.

A ceramic electronic component such as a multilayer ceramic substrate and a multilayer ceramic capacitor includes a ceramic insulator, an inner conductor embedded in the ceramic insulator, and an outer conductor provided on the outer surface of the ceramic insulator. In such a ceramic electronic component, a conductor paste film to be an inner conductor or an outer conductor is generally formed using a conductor paste on a green sheet containing a raw material powder of a ceramic insulator, and then a conductor paste film is formed. A plurality of green sheets are laminated to form a green laminate, which is obtained by firing the green laminate. Furthermore, a plating layer is formed on the surface of the outer conductor by performing a plating treatment for the purpose of improving heat resistance, solder wettability and the like.

When manufacturing a ceramic electronic component by the above method, both the conductive paste and the green sheet shrink during firing, and a gap may be formed between the internal conductor and the ceramic insulator due to the difference in the shrinkage behavior of both. is there. In this case, a liquid such as a plating solution intrudes into the space, and as a result, the electrical characteristics of the ceramic electronic component may be degraded, which may lead to a decrease in reliability.

Then, the method of patent document 1 and patent document 2 is proposed as a means to prevent permeation of liquids, such as a plating solution. Patent Document 1 discloses a method of plugging pores in a ceramic surface portion of a sintered magnetic material, dielectric or the like in a vacuum by impregnating the synthetic resin in a vacuum, and Patent Document 2 discloses a method of wet plating during the process of wet plating. In the method described in U.S. Pat. No. 5,075,095, the voids of the ceramic body and the terminal electrode are filled with an organic solvent, and the organic solvent is removed by evaporation after the process is completed.

Japanese Examined Patent Publication 1-55566 JP-A-8-64463

The methods described in Patent Document 1 and Patent Document 2 are methods of filling the air gaps by post-processing, so the number of steps for manufacturing the ceramic electronic component will increase. Furthermore, since the resin material used in Patent Document 1 has a thermal expansion coefficient different from that of the ceramic material, when a thermal shock is applied to the ceramic electronic component, peeling or cracking may occur between the two. Moreover, since the method of using an organic solvent like patent document 2 is a method of obstruct | occluding a space | gap temporarily at the time of plating process, after an organic solvent volatilizes, the space | gap which a liquid can infiltrate will remain.

The present invention has been made to solve the above problems, and it is difficult to form a void between the inner conductor layer and the ceramic insulator, and a ceramic electronic component capable of preventing the infiltration of a liquid from the outside, And, it is an object of the present invention to provide a method of manufacturing the ceramic electronic component.

In order to achieve the above object, a ceramic electronic component of the present invention is a ceramic electronic component including a ceramic insulator and an inner conductor layer provided inside the ceramic insulator, wherein the inner conductor layer is a metal. And a metal oxide containing at least one metal element selected from the group consisting of Ti, Mg and Zr, and at least one selected from the group consisting of Ti, Mg and Zr in the inner conductor layer. The first insulator includes the one or more metal elements, and the first insulator region discontinuous with the ceramic insulator is present in a dispersed manner, and the entire circumference of the inner conductor layer in contact with the ceramic insulator is the first insulator. A second insulator region containing the same metal element as the metal element contained in the region is characterized by being present.

In the ceramic electronic component of the present invention, the first insulator region and the second insulator region containing at least one metal element selected from the group consisting of Ti, Mg and Zr are respectively provided inside and around the inner conductor layer. Existing. This is because the component of the metal oxide contained in the inner conductor layer does not diffuse to the ceramic insulator during firing to produce a ceramic electronic component, and the inside of the inner conductor layer and the inner conductor layer and the ceramic insulation It means to stay between the body. As a result, the shrinkage of the inner conductor layer at the time of firing is suppressed, and a void is less likely to be formed between the inner conductor layer and the ceramic insulator.
As described above, in the ceramic electronic component of the present invention, the formation of the air gap between the internal conductor layer and the ceramic insulator can be suppressed, so that the penetration of the liquid such as the plating solution from the outside can be prevented. it can. As a result, the occurrence of migration and the like is suppressed, and a short between the conductors is reduced, leading to an improvement in reliability. Furthermore, defects such as expansion of the outer conductor, explosion of the solder, formation of voids inside the solder, and discoloration of the outer conductor, which are problems when mounting the ceramic electronic component due to the infiltration of the liquid, can be reduced.

In the ceramic electronic component of the present invention, the ceramic insulator preferably contains the same metal element as the metal element contained in the first insulator region and the second insulator region.
When the ceramic insulator contains the same metal element as the metal element contained in the first insulator region and the second insulator region, the sintering behavior of the inner conductor layer becomes close to the sintering behavior of the ceramic insulator, The formation of air gaps between the inner conductor layer and the ceramic insulator can be further suppressed.

When the ceramic insulator contains the same metal element as the metal element contained in the first insulator region and the second insulator region, the concentration of the metal element contained in the ceramic insulator is the same as that in the first insulator region. The concentration is preferably lower than the concentration of the metal element and lower than the concentration of the metal element in the second insulator region.
This is because, even when the ceramic insulator contains the same metal element as the metal element contained in the first insulator region and the second insulator region, the component of the metal oxide contained in the inner conductor layer is the inner conductor layer Of the inner conductor and between the inner conductor layer and the ceramic insulator. Therefore, the shrinkage of the inner conductor layer at the time of firing is suppressed, and a void is less likely to be formed between the inner conductor layer and the ceramic insulator.

In the ceramic electronic component of the present invention, the internal conductor layer is preferably exposed to the surface of the ceramic insulator. Preferably, the ceramic electronic component of the present invention further comprises an outer conductor provided on the surface of the ceramic insulator, and the inner conductor layer is covered by the outer conductor.
As described above, even if the ceramic electronic component has a structure in which the liquid is easily infiltrated from the outside, the formation of the air gap between the internal conductor layer and the ceramic insulator can be suppressed, so that the liquid such as the plating solution It is possible to prevent the intrusion from the outside.

In the ceramic electronic component of the present invention, it is preferable that the length of the air gap generated in a portion in contact with the upper surface of the inner conductor layer in the lower surface of the inner conductor layer is 100 μm or less.
In the ceramic electronic component of the present invention, among the lower surface of the inner conductor layer, formation of the air gap formed in the portion in contact with the upper surface of the inner conductor layer is suppressed. can do.

The method for producing a ceramic electronic component according to the present invention is the method for producing a ceramic electronic component, comprising the steps of: preparing a plurality of green sheets containing a raw material powder of a ceramic insulator; metal powder; metal oxide powder or metal A conductive paste comprising an oxide precursor powder and an organic vehicle, wherein the metal oxide powder or the metal oxide precursor powder comprises at least one metal element selected from the group consisting of Ti, Mg and Zr. A step of preparing, a step of forming a conductor paste film to be an inner conductor layer by applying the conductor paste to at least one main surface of the green sheet, and a plurality of the green sheets are laminated. Manufacturing a green laminate in which the conductive paste film is formed between the green sheets, baking the green laminate, Characterized in that it comprises.

In the method for producing a ceramic electronic component of the present invention, the metal powder is sintered before the component of the metal oxide derived from the metal oxide powder or the metal oxide precursor powder diffuses into the ceramic insulator. An oxide may be deposited within the inner conductor layer and between the inner conductor layer and the ceramic insulator to form the first insulator region and the second insulator region described above. Thereby, contraction of the inner conductor layer at the time of firing can be suppressed. As a result, a void is not easily formed between the internal conductor layer and the ceramic insulator, and a ceramic electronic component capable of preventing the entry of liquid from the outside can be manufactured.

In the method for producing a ceramic electronic component of the present invention, the specific surface area of the metal oxide powder or the metal oxide precursor powder is preferably 6 m ² / g or more and 90 m ² / g or less.
If the specific surface area of the metal oxide powder or metal oxide precursor powder contained in the conductor paste is in the above range, the metal oxide powder or metal oxide precursor powder is likely to be trapped between the sintered metal powders. Become. That is, since the component of the metal oxide contained in the internal conductor layer hardly diffuses to the ceramic insulator, the contraction of the internal conductor layer at the time of firing is further suppressed.

In the method for producing a ceramic electronic component of the present invention, the specific surface area-converted particle diameter of the metal oxide powder or the metal oxide precursor powder is D _Osf [nm], and the volume-based median diameter of the metal powder is D _M50 It is preferable that 2.28 ≦ _{DM 50} / D _Osf ≦ 105.5, where
When the particle size of the metal oxide powder or the metal oxide precursor powder is smaller than the particle size of the metal powder, the metal oxide powder or the metal oxide precursor powder is likely to be trapped between the sintered metal powders. That is, since the component of the metal oxide contained in the internal conductor layer hardly diffuses to the ceramic insulator, the contraction of the internal conductor layer at the time of firing is further suppressed.

In the method for producing a ceramic electronic component of the present invention, the sintering start temperature of the metal powder is preferably equal to or less than the sintering start temperature of the green sheet.
When sintering of the green sheet starts at a low temperature, the liquid phase component of the ceramic insulator may react with the metal oxide in the conductor paste, and the first insulator region and the second insulator region may not be formed. Therefore, by setting the sintering start temperature of the metal powder to the sintering start temperature or less of the green sheet, the first insulator region and the second insulator region can be reliably formed.

In the method of manufacturing a ceramic electronic component of the present invention, the raw material powder of the ceramic insulator preferably contains SiO ₂ , Al ₂ O ₃ and a Ba compound.
The above raw material powder can be sintered at a sintering temperature of 1000 ° C. or less, and simultaneous sintering with Ag or Cu is possible.

According to the present invention, it is difficult to form a gap between the inner conductor layer and the ceramic insulator, and a ceramic electronic component capable of preventing the infiltration of liquid from the outside, and a method of manufacturing the ceramic electronic component are provided. can do.

FIG. 1 is a cross-sectional view schematically showing an example of a multilayer ceramic substrate. FIG. 2 is a cross-sectional view schematically showing an example of the laminated ceramic capacitor. Fig.3 (a) is a perspective view which shows typically the internal conductor layer vicinity of the ceramic electronic component of this invention, FIG.3 (b) is a BB sectional drawing of FIG. 3 (a), FIG.3 (c) is CC sectional view taken on the line of FIG. 3 (a). FIGS. 4A to 4D are reflection electron images in the vicinity of the inner conductor layers of the ceramic electronic components S-1 to S-4 and mapping images of the Ti element. 5A to 5D are reflection electron images of the entire ceramic electronic components S-1 to S-4 and mapping images of the Ti element. FIG. 6A is a reflection electron image in the vicinity of the inner conductor layer of the ceramic electronic component S-11 and a mapping image of Mg element, and FIG. 6B is a reflection electron image in the vicinity of the inner conductor layer of the ceramic electronic component S-12 and the Zr element Mapping image of FIG. 7 is a photomicrograph of the exposed surface of the ceramic electronic component S-4. FIG. 8 is a photomicrograph of the exposed surface of the ceramic electronic component S-15.

Hereinafter, the ceramic electronic component of the present invention and the method of manufacturing the ceramic electronic component will be described.
However, the present invention is not limited to the following configurations, and can be appropriately modified and applied without departing from the scope of the present invention.
Combinations of two or more of the individual desirable features of the invention described below are also inventions.
It is needless to say that each embodiment shown below is an exemplification, and partial replacement or combination of the configurations shown in the different embodiments is possible.

As one embodiment of the ceramic electronic component of the present invention, a multilayer ceramic substrate will be described as an example.
FIG. 1 is a cross-sectional view schematically showing an example of a multilayer ceramic substrate.
A multilayer ceramic substrate 1 shown in FIG. 1 includes a ceramic insulator 11 formed by laminating a plurality of ceramic layers, and an internal conductor layer 12 provided inside the ceramic insulator 11. The inner conductor layer 12 is disposed between the ceramic layers as a wiring conductor, and is formed substantially parallel to the main surface of the ceramic insulator 11.
Furthermore, multilayer ceramic substrate 1 is provided on outer conductor layer 13 provided on one main surface of multilayer ceramic substrate 1 and the other main surface of multilayer ceramic substrate 1 as a wiring conductor other than internal conductor layer 12. An outer conductor layer 14 and a via conductor 15 electrically connected to any of the inner conductor layer 12, the outer conductor layer 13, and the outer conductor layer 14 and provided to penetrate the ceramic layer in the thickness direction There is.

A chip component (not shown) is mounted on the one main surface of the multilayer ceramic substrate 1 in a state of being electrically connected to the outer conductor layer 13. The chip component mounted on the multilayer ceramic substrate 1 may be the ceramic electronic component of the present invention. The outer conductor layer 14 formed on the other main surface of the multilayer ceramic substrate 1 is used as an electrical connection means when the multilayer ceramic substrate 1 on which the chip component is mounted is mounted on a mother board (not shown).

The ceramic electronic component of the present invention is not limited to a multilayer ceramic substrate, and can be applied to chip components mounted on a multilayer ceramic substrate, for example, multilayer ceramic electronic components such as multilayer ceramic capacitors, multilayer inductors, multilayer filters, etc. It is also possible to apply to various ceramic electronic components other than laminated ceramic electronic components.

FIG. 2 is a cross-sectional view schematically showing an example of the laminated ceramic capacitor.
The multilayer ceramic capacitor 2 shown in FIG. 2 includes a ceramic insulator 21 formed by laminating a plurality of dielectric layers, and inner layer electrodes 22a to 22f as internal conductor layers provided inside the ceramic insulator 21. There is. The inner layer electrodes 22 a to 22 f are disposed between the dielectric layers and formed substantially parallel to the main surface of the ceramic insulator 21. An external electrode 23a as an external conductor is formed on one end surface of the ceramic insulator 21, and an external electrode 23b as an external conductor is formed on the other end surface of the ceramic insulator 21.

The inner layer electrodes 22a to 22f are arranged in parallel in the stacking direction. The inner layer electrodes 22a, 22c and 22e are exposed at one end face of the ceramic insulator 21 and are electrically connected to the outer electrode 23a. The inner layer electrodes 22b, 22d and 22f are exposed at the other end face of the ceramic insulator 21 and are electrically connected to the external electrode 23b. Then, electrostatic capacitance is generated between the facing surfaces of the inner layer electrodes 22a, 22c and 22e and the inner layer electrodes 22b, 22d and 22f.

The ceramic electronic component of the present invention preferably has a structure in which the inner conductor layer is exposed on the surface of the ceramic insulator, or a structure in which the inner conductor layer is covered by the outer conductor.
In the ceramic electronic component of the present invention, the outer conductor is provided on the surface of the ceramic insulator, and may be a metal case or the like provided for an electromagnetic shield besides the above-described outer electrode.

It is preferable that the ceramic insulator which comprises the ceramic electronic component of this invention contains a low temperature sintering ceramic material.
The low-temperature sintered ceramic material means, among ceramic materials, a material which can be sintered at a firing temperature of 1000 ° C. or less and can be co-fired with Ag or Cu.

As a low temperature sintered ceramic material contained in the ceramic insulator, for example, a glass composite low temperature sintered ceramic material formed by mixing a borosilicate glass with a ceramic material such as quartz, alumina, forsterite, etc., ZnO-MgO-Al ₂ O ₃ -SiO ₂ based crystallized glass-based low-temperature co-fired ceramic material with crystallized glass, _BaO-Al 2 O 3 -SiO ₂ based ceramic material and _{Al 2 O 3 -CaO-SiO 2} -MgO-B 2 Non-glass-based low-temperature sintered ceramic materials and the like using O ₃ -based ceramic materials and the like can be mentioned.

The inner conductor layer constituting the ceramic electronic component of the present invention contains a metal and a metal oxide.
As a metal contained in the inner conductor layer, for example, Au, Ag, Cu, Pt, Ta, W, Ni, Fe, Cr, Mo, Ti, Pd, Ru and an alloy containing one of these metals as a main component Etc. The inner conductor layer preferably contains Au, Ag or Cu as a metal, and more preferably Ag or Cu. Au, Ag and Cu are particularly suitable when the ceramic electronic component is for high frequency applications because of their low resistance.

The metal oxide contained in the inner conductor layer contains at least one metal element selected from the group consisting of Ti, Mg and Zr, and typical substances include TiO ₂ , MgO and ZrO _2. Be These metal oxides may be used alone or in combination of two or more. The inner conductor layer preferably contains, as a metal oxide, a metal oxide containing a Ti element such as TiO ₂ .

In the ceramic electronic component of the present invention, the ceramic insulator and the discontinuous first insulator region are dispersed and present inside the inner conductor layer, and the second insulator region is present around the inner conductor layer. Do. The first insulator region contains at least one metal element selected from the group consisting of Ti, Mg and Zr, and the second insulator region is the same as the metal element contained in the first insulator region. Contains metallic elements.

The metal elements contained in the first insulator region and the second insulator region coincide with the metal elements constituting the metal oxide contained in the inner conductor layer. That is, when the metal oxide contained in the inner conductor layer is a metal oxide containing Ti, for example, TiO ₂ , the metal element contained in the first insulator region and the second insulator region is Ti, and the inside When the metal oxide contained in the conductor layer is a metal oxide containing Mg, for example, MgO, the metal element contained in the first insulator region and the second insulator region is Mg, and is contained in the internal conductor layer When the metal oxide to be formed is a metal oxide containing Zr, for example, ZrO ₂ , the metal element contained in the first insulator region and the second insulator region is Zr. When two or more types of metal oxides are contained in the inner conductor layer, at least one of the metal oxides may be contained in the first insulator region and the second insulator region.

Fig.3 (a) is a perspective view which shows typically the internal conductor layer vicinity of the ceramic electronic component of this invention, FIG.3 (b) is a BB sectional drawing of FIG. 3 (a), FIG.3 (c) is CC sectional view taken on the line of FIG. 3 (a). FIGS. 3A and 3B show an example in which one end of the internal conductor layer 32 is exposed to the surface of the ceramic insulator 31. FIG.
As shown in FIGS. 3B and 3C, the ceramic insulator 31 and the discontinuous first insulator region 41 are dispersedly present in the inner conductor layer 32, and the inner conductor layer 32 is formed. There is a second insulator region 42 around the.

In the present specification, at least one metal element selected from the group consisting of Ti, Mg and Zr is identified in and around the inner conductor layer by elemental analysis by wavelength dispersive X-ray spectroscopy (WDX). Then, each region can be made into a first insulator region and a second insulator region.

In the ceramic electronic component of the present invention, the first insulator region is a region discontinuous with the ceramic insulator. That is, the first insulator region is a region which is not connected to the ceramic insulator outside the inner conductor layer but is surrounded by the metal of the inner conductor layer and is independent of the ceramic insulator. The first insulator region is composed of a plurality of small regions, and the respective small regions are present in a dispersed manner. The size of each small area is not particularly limited, and the size of each small area may be the same or different.

In the ceramic electronic component of the present invention, the second insulator region is preferably present uniformly around the inner conductor layer, but may not be present at a part of the inner conductor layer.
Also, the second insulator region may be present between the inner conductor layer and the ceramic insulator. Among them, the second insulator region is preferably present in a region of 3 μm in thickness between the inner conductor layer and the ceramic insulator. FIG. 3B shows an example in which the second insulator region 42 is present between the internal conductor layer 32 and the ceramic insulator 31 in a region of 3 μm in thickness.

In the ceramic electronic component of the present invention, the ceramic insulator preferably contains the same metal element as the metal element contained in the first insulator region and the second insulator region. That is, when the metal element contained in the first insulator region and the second insulator region is Ti, the ceramic insulator preferably contains the Ti element, and the first insulator region and the second insulator region are When the metal element contained is Mg, the ceramic insulator preferably contains an Mg element, and when the metal element contained in the first insulator region and the second insulator region is Zr, the ceramic insulation It is preferable that the body contain the Zr element. When two or more types of metal elements are contained in the first insulator region and the second insulator region, the ceramic insulator may contain at least one of the metal elements.

In the ceramic electronic component of the present invention, the concentration of the metal element contained in the ceramic insulator is lower than the concentration of the metal element in the first insulator region and lower than the concentration of the metal element in the second insulator region Is preferred.

In the present specification, the concentration of the above-mentioned metal element contained in the ceramic insulator is a region of 3 μm in thickness (region 43 in FIG. 3 (b)) separated by 20 μm from the interface between the internal conductor layer and the second insulator region. The concentration of the above metal element in
In the above region, if the strength of at least one metal element selected from the group consisting of Ti, Mg and Zr by the above-mentioned WDX is smaller than the strength of the above metal element in the first insulator region and the second insulator region It can be said that the concentration of the metal element contained in the ceramic insulator is lower than the concentration of the metal element in the first insulator region and lower than the concentration of the metal element in the second insulator region.
The interface between the inner conductor layer and the second insulator region is the strength of the element (for example, Cu) of the metal component contained in the inner conductor layer when elemental analysis is performed by WDX under the conditions described in the examples. Means a site where is less than 600.

In the ceramic electronic component of the present invention, in the lower surface of the inner conductor layer, the length of the air gap generated in the portion (portion A in FIG. 3A and FIG. 3C) in contact with the upper surface of the inner conductor layer is 100 μm It is preferable that it is the following. In particular, the length of the air gap is preferably 0 μm, that is, no air gap is generated in the portion.
In this specification, the surface on which the inner conductor layer is formed is referred to as "the lower surface of the inner conductor layer", and the other surface is referred to as "the upper surface of the inner conductor layer". For example, when the internal conductor layer having a rectangular parallelepiped shape is formed on the ceramic layer, the bottom surface of the internal conductor layer in contact with the ceramic layer corresponds to “the lower surface of the internal conductor layer” and a plane facing the bottom surface The side surfaces collectively correspond to the “upper surface of the inner conductor layer”.
In addition, the length of the said space | gap measures the length of the fluorescent solution which penetrated between the internal conductor layer and the ceramic insulator, after impregnating a ceramic electronic component with a fluorescent solution so that Example may demonstrate. It is determined by

The ceramic electronic component of the present invention is preferably manufactured as follows.

First, a plurality of green sheets containing raw material powders of ceramic insulators are prepared.
The green sheet is obtained by forming a slurry containing a powder of a ceramic raw material such as a low temperature sintered ceramic material, an organic binder and a solvent into a sheet by a doctor blade method or the like. The slurry may contain various additives such as a dispersant and a plasticizer.

The raw material powder of the ceramic insulator preferably contains SiO ₂ , Al ₂ O ₃ and a Ba compound. Furthermore, it is more preferable that the raw material powder of a ceramic insulator contains the same metallic element as the metallic element contained in the conductor paste mentioned later. The powder of the ceramic material contained in the slurry, e.g., a SiO _2, and _Al 2 _{O 3,} it is preferable to use a powder containing a BaCO _3, and SiO _2, and _Al 2 _{O 3,} and BaCO _3, It is more preferable to use a powder containing at least one selected from the group consisting of TiO ₂ , Mg (OH) ₂ and ZrO ₂ . By heating, BaCO ₃ changes to BaO, and Mg (OH) ₂ changes to MgO. MgO powder may be used instead of Mg (OH) ₂ powder.

Separately, a conductor paste containing metal powder, metal oxide powder or metal oxide precursor powder, and an organic vehicle is prepared.
As a metal powder, it is preferable to use Cu powder. Further, as the organic vehicle, for example, an ethyl cellulose resin, an acrylic resin, a polyvinyl butyral resin and the like can be used, and among them, it is preferable to use an ethyl cellulose resin.

The metal oxide powder or the metal oxide precursor powder contains at least one metal element selected from the group consisting of Ti, Mg and Zr. The metal oxide precursor is one that changes to a metal oxide by heating. As the metal oxide powder or the metal oxide precursor powder, for example, a powder containing at least one selected from the group consisting of TiO ₂ , Mg (OH) ₂ and ZrO ₂ can be used. Among them, it is preferable to use TiO ₂ powder as the metal oxide powder. By heating, Mg (OH) ₂ changes to MgO. MgO powder may be used instead of Mg (OH) ₂ powder.

The specific surface area (SSA) of the metal oxide powder or the metal oxide precursor powder is preferably 6 m ² / g or more, more preferably 20 m ² / g or more, and still more preferably 50 m ² / g or more. The specific surface area of the metal oxide powder or the metal oxide precursor powder is preferably 90 m ² / g or less. In particular, when TiO ₂ powder is used as the metal oxide powder, the specific surface area of the TiO ₂ powder is preferably in the above range.
The specific surface area of the metal oxide powder or metal oxide precursor powder is the SSA measuring device (Muntech brand name Macsorb (registered trademark)) by BET (Brunauer, Emmet and Teller's equation) one-point method using N ₂ gas. It is the value measured using.

_Assuming that the specific surface area-converted particle diameter of the metal oxide powder or metal oxide precursor powder is D _Osf [nm] and the volume-based median diameter of the metal powder is D _M50 [nm], 2.28 ≦ D _M50 / D _Osf It is preferably ≦ 105.5, and more preferably 18.8 ≦ _{DM 50} / D _Osf ≦ 105.5. In particular, when TiO ₂ powder is used as the metal oxide powder, it is preferable that D _M50 / D _Osf be in the above range.
The specific surface area-equivalent particle diameter D _Osf [nm] of the metal oxide powder or metal oxide precursor powder is the specific surface area of the metal oxide powder or metal oxide precursor powder measured by the BET one-point method. ² / g], and the density of the constituent material of the metal oxide powder or the metal oxide precursor powder is [[g / cm ³ ], the formula “D _Osf = (6 × 10 ³ ) / (s × ρ) Is the value obtained from
The volume-based median diameter D _M50 [nm] of the metal powder is a value measured using a laser diffraction / scattering particle size distribution measuring apparatus (LA series manufactured by Horiba, Ltd.).

1.5 weight% or more is preferable, as for content of the metal oxide powder or metal oxide precursor powder in a conductor paste, 2.0 weight% or more is more preferable, 2.5 weight% or more is more preferable, and 4.0% by weight or less is preferable, and 3.5% by weight or less is more preferable.

The sintering start temperature of the metal powder is preferably equal to or less than the sintering start temperature of the green sheet.
Here, with the sintering start temperature of the metal powder and the green sheet, a main shrinkage temperature range, that is, a temperature at which the amount of shrinkage is maximized in a temperature range of 400 ° C. or more and 1000 ° C. or less In the region, when the tangent of the point where the TMA curve shows inflection and the tangent of the TMA curve in the range of 600 ° C. to 700 ° C. are drawn, the temperature is indicated by the intersection of the two lines.

The conductive paste is applied to at least one of the main surfaces of the green sheet to form a conductive paste film to be an internal conductive layer. As necessary, a conductor paste film to be an outer conductor layer and a conductor paste body to be a via conductor are formed on a specific green sheet. As a conductor paste for forming an outer conductor layer and a via conductor, it is preferable to use a conductor paste for forming an inner conductor layer.

Subsequently, by laminating a plurality of green sheets, a green laminate in which the conductor paste film is formed between the green sheets is produced.
The green laminate is preferably produced by laminating green sheets previously formed into a sheet as described above, but it is produced by repeating forming the ceramic slurry into a sheet at the same place. It may be done.

The green laminate is then fired. As a result, a ceramic electronic component comprising a ceramic insulator and an inner conductor layer provided inside the ceramic insulator is obtained.

In the method for producing a ceramic electronic component of the present invention, the metal powder is sintered before the component of the metal oxide derived from the metal oxide powder or the metal oxide precursor powder diffuses into the ceramic insulator. An oxide may be deposited within the inner conductor layer and between the inner conductor layer and the ceramic insulator to form the first insulator region and the second insulator region described above. Thereby, contraction of the inner conductor layer at the time of firing can be suppressed. As a result, a void is not easily formed between the internal conductor layer and the ceramic insulator, and a ceramic electronic component capable of preventing the entry of liquid from the outside can be manufactured.

In the method for producing a ceramic electronic component of the present invention, a constrained green sheet mainly composed of an inorganic material (Al ₂ O ₃ or the like) which does not substantially sinter at the sintering temperature of the green laminate is prepared. The green laminate may be fired with the constrained green sheet disposed on the outermost surface of the body. In this case, since the constrained green sheet does not substantially sinter during firing, it does not shrink and acts on the laminate to suppress the shrinkage in the main surface direction. As a result, the dimensional accuracy of the ceramic electronic component can be enhanced.

When the ceramic electronic component of the present invention includes an outer conductor such as an outer electrode, a plated layer may be formed on the surface of the outer conductor after firing by performing electrolytic plating or electroless plating.

Hereinafter, examples showing the ceramic electronic component of the present invention and the method for manufacturing the ceramic electronic component more specifically will be shown. The present invention is not limited to only these examples.

[Production of green sheet]
As starting materials, powders of SiO ₂ , Al ₂ O ₃ , BaCO ₃ , TiO ₂ , Mg (OH) ₂ and ZrO ₂ each having an average particle diameter (D ₅₀ ) of 2.0 μm or less were prepared. These starting material powders were weighed to have a predetermined composition ratio, wet mixed and ground, and dried to obtain a mixture. The obtained mixture was heat-treated under a reducing atmosphere to obtain a raw material powder for a green sheet of a ceramic insulator. By this heat treatment, BaCO ₃ was changed to BaO, and Mg (OH) ₂ was changed to MgO.

An organic binder, a dispersant and a plasticizer were added to the above raw material powder, and mixed and ground so that the average particle diameter (D ₅₀ ) of the raw material powder was 1.5 μm or less, to obtain a ceramic slurry. Next, the ceramic slurry was formed into a sheet on a base film by a doctor blade method, and dried to obtain a green sheet whose thickness was adjusted so that the thickness after firing was 20 μm.

[Preparation of conductor paste]
As starting materials, metal powders shown in Table 1, metal oxide powders shown in Table 2, and organic vehicles shown in Table 3 were prepared.

The particle size ( _DM10 , _DM50 and _DM90 ) of the metal powder in Table 1 was measured using a laser diffraction / scattering particle size distribution analyzer (LA series manufactured by Horiba, Ltd.). As a measurement solvent, a mixture of ethyl alcohol and isopropyl alcohol was used. The SSA (specific surface area) of the metal powder and the metal oxide powder in Tables 1 and 2 was measured using an SSA measuring apparatus (MUNTECH brand name Macsorb (registered trademark)) according to a BET one-point method using N ₂ gas. The densities of the metal powder and the metal oxide powder in Tables 1 and 2 were measured using a dry-type automatic densitometer (trade name AccuPic series manufactured by Shimadzu Corporation). The density of the organic vehicle in Table 3 was measured using a specific gravity cup (manufactured by Yasuda Seiki Co., Ltd.).

The starting materials shown in Tables 1 to 3 were prepared to have the composition ratios shown in Table 4 and dispersed by a three roll mill to obtain conductor pastes P-1 to P-15.

[Fabrication of ceramic electronic components]
A conductor paste film to be an internal conductor layer was formed on the surface of the green sheet by screen printing using conductor pastes P-1 to P-15. A predetermined number of green sheets on which the conductor paste film was formed were laminated, and after sandwiching with a green sheet on which the conductor pattern film was not formed, they were crimped to produce a green laminate. Thereafter, firing is performed at 800 to 1000 ° C. for 60 to 180 minutes in a reducing atmosphere to obtain a ceramic electronic component in which an internal conductor layer is provided inside the ceramic insulator. The sample numbers S-1 to S-15 corresponding to the numbers of the conductor pastes were given to the obtained ceramic electronic components.

[Elemental analysis by WDX]
The ceramic electronic components S-1 to S-15 were polished using a mechanical polishing machine to expose the cross sections of the ceramic electronic components S-1 to S-15. Using a WDX (wavelength dispersive X-ray spectroscopic analysis) measuring apparatus (trade name JXA-8530F manufactured by JEOL) in which flat milling processing and carbon coating processing were performed on the cross sections of the ceramic electronic components S-1 to S-15 Elemental analysis was performed. The measurement conditions of WDX are shown in Table 5.

FIGS. 4A to 4D are reflection electron images in the vicinity of the inner conductor layers of the ceramic electronic components S-1 to S-4 and mapping images of the Ti element. In FIGS. 4A to 4D, the left side is a backscattered electron image, and the right side is a mapping image of Ti element.
As shown in FIGS. 4A to 4D, in the ceramic electronic components S-1 to S-4 in which the inner conductor layer is formed using the conductor pastes P-1 to P-4 containing TiO ₂ powder as the metal oxide powder, It can be confirmed that the ceramic insulator and the discontinuous first insulator region are dispersed and present inside the inner conductor layer, and the second insulator region is present around the inner conductor layer. Furthermore, as the SSA (specific surface area) of the TiO ₂ powder increases from FIG. 4A to FIG. 4D, that is, as the specific surface area converted particle diameter D _Osf decreases, the size of the small region constituting the first insulator region decreases. It can be confirmed that it will be.

5A to 5D are reflection electron images of the entire ceramic electronic components S-1 to S-4 and mapping images of the Ti element. In FIGS. 5A to 5D, the left side is a backscattered electron image, and the right side is a mapping image of Ti element.
In FIGS. 5A to 5D as well as FIGS. 4A to 4D, the ceramic insulator and the discontinuous first insulator region are dispersed and present inside the inner conductor layer, and around the inner conductor layer. It can be confirmed that the second insulator region is present. On the other hand, it can be confirmed that the strength of the Ti element is smaller in the region separated by 20 μm from the interface between the inner conductor layer and the second insulator region than in the first insulator region and the second insulator region. Therefore, it can be seen that the concentration of Ti element contained in the ceramic insulator is lower than the concentration of Ti element in the first insulator region and the second insulator region.

Although not shown, ceramic electronic components S-5 to S-8 in which an inner conductor layer is formed using conductor pastes P-5 to P-8 in which the particle diameter of Cu powder which is a metal powder is changed, and metal oxides Also in the ceramic electronic components S-13 and S-14 in which the inner conductor layer is formed using the conductor pastes P-13 and P-14 in which the content of the TiO ₂ powder which is a powder is changed, the ceramic electronic components S-3 and Similarly, it was confirmed that the ceramic insulator and the discontinuous first insulator region were dispersed in the inner conductor layer, and the second insulator region was present around the inner conductor layer.

FIG. 6A is a reflection electron image in the vicinity of the inner conductor layer of the ceramic electronic component S-11 and a mapping image of Mg element, and FIG. 6B is a reflection electron image in the vicinity of the inner conductor layer of the ceramic electronic component S-12 and the Zr element Mapping image of 6A and 6B, the left side is a backscattered electron image, and the right side is a mapping image of Mg element or Zr element.
As shown to FIG. 6A, ceramic electronic component S-11 which formed the internal conductor layer using the conductor paste P-11 which contains MgO powder as metal oxide powder, and as shown to FIG. 6B, metal oxide powder In the ceramic electronic component S-12 in which the inner conductor layer is formed using the conductor paste P-12 containing ZrO ₂ powder as a ceramic, although the second insulator region does not exist in a part of the periphery of the inner conductor layer, Similar to S-1 to S-4, the ceramic insulator and the discontinuous first insulator region are dispersed in the inner conductor layer, and the second insulator region is present around the inner conductor layer. It can be confirmed.

On the other hand, a ceramic electronic component S-9 in which an inner conductor layer is formed using a conductor paste P-9 containing Al ₂ O ₃ powder as a metal oxide powder, and a conductor paste P containing SiO ₂ powder as a metal oxide powder In the ceramic electronic component S-10 in which the inner conductor layer was formed using -10, the presence of the first insulator region and the second insulator region could not be confirmed. It is considered that this is because the metal oxide powder contained in the conductor paste has reacted with the raw material powder of the ceramic insulator. Further, also in the ceramic electronic component S-15 in which the inner conductor layer is formed using the conductor paste P-15 containing no metal oxide powder, the existence of the first insulator region and the second insulator region may be confirmed. could not.

[Confirmation of air gap generated between inner conductor layer and ceramic insulator]
In order to confirm the voids generated between the inner conductor layer and the ceramic insulator, each ceramic electronic component was vacuum impregnated with a fluorescent solution and then dried using a dryer. Thereafter, the ceramic electronic component was polished using a mechanical polisher until the surface including the inner conductor layer was exposed. The polished surface was confirmed using a microscope of an Hg light source, and it was confirmed whether the fluorescent solution was invading between the internal conductor layer and the ceramic insulator.

FIG. 7 is a photomicrograph of the exposed surface of the ceramic electronic component S-4, and FIG. 8 is a photomicrograph of the exposed surface of the ceramic electronic component S-15.
In the ceramic electronic component S-4 in which the first insulator region and the second insulator region exist, as shown in FIG. 7, the fluorescent liquid does not infiltrate as shown in FIG. 7, while the first insulator region and the second insulator region In the ceramic electronic component S-15 in which there is no existent, it can be confirmed that the fluorescent liquid infiltrates as shown in FIG. From the above results, it can be seen that the formation of the air gap generated between the internal conductor layer and the ceramic insulator is suppressed by forming the first insulator region and the second insulator region.

1 Multilayer ceramic substrate (ceramic electronic components)
2 Multilayer ceramic capacitor (ceramic electronic components)
11, 21, 31 ceramic insulators 12, 32 inner conductor layers 13, 14 outer conductor layer 15 via conductors 22a, 22b, 22c, 22d, 22e, 22f inner layer electrodes (inner conductor layers)
23a, 23b external electrode 41 first insulator region 42 second insulator region 43 3 μm thick region 44 separated from the interface between the inner conductor layer and the second insulator region with an inner conductor layer and a second insulator region A portion of the lower surface of the inner conductor layer in contact with the upper surface of the inner conductor layer

Claims (11)

A ceramic electronic component comprising a ceramic insulator and an inner conductor layer provided inside the ceramic insulator,
The inner conductor layer includes a metal and a metal oxide containing at least one metal element selected from the group consisting of Ti, Mg and Zr,
At least one metal element selected from the group consisting of Ti, Mg and Zr is contained in the inner conductor layer, and the ceramic insulator and the discontinuous first insulator region are present in a dispersed manner.
A ceramic electronic component characterized in that a second insulator region containing the same metal element as the metal element contained in the first insulator region is present all around the inner conductor layer in contact with the ceramic insulator. . The ceramic electronic component according to claim 1, wherein the ceramic insulator contains the same metal element as the metal element contained in the first insulator region and the second insulator region. The concentration of the metal element contained in the ceramic insulator is lower than the concentration of the metal element in the first insulator region, and lower than the concentration of the metal element in the second insulator region. Ceramic electronic components. The ceramic electronic component according to any one of claims 1 to 3, wherein the inner conductor layer is exposed on the surface of the ceramic insulator. It further comprises an outer conductor provided on the surface of the ceramic insulator,
The ceramic electronic component according to any one of claims 1 to 3, wherein the inner conductor layer is covered by the outer conductor. The ceramic electronic component according to any one of claims 1 to 5, wherein a length of an air gap generated in a portion of the lower surface of the inner conductor layer in contact with the upper surface of the inner conductor layer is 100 μm or less. A method of manufacturing a ceramic electronic component according to any one of claims 1 to 6, wherein
Preparing a plurality of green sheets containing raw material powder of ceramic insulator;
The metal powder, the metal oxide powder or the metal oxide precursor powder, and the organic vehicle, wherein the metal oxide powder or the metal oxide precursor powder is at least selected from the group consisting of Ti, Mg and Zr. Preparing a conductive paste containing one metal element;
Forming a conductor paste film to be an internal conductor layer by applying the conductor paste to at least one main surface of the green sheet;
Producing a green laminate in which a plurality of the green sheets are stacked and the conductive paste film is formed between the green sheets;
And b. Firing the green laminate. The method for producing a ceramic electronic component according to claim 7, wherein the specific surface area of the metal oxide powder or the metal oxide precursor powder is 6 m ² / g or more and 90 m ² / g or less. _Assuming that the specific surface area-equivalent particle diameter of the metal oxide powder or the metal oxide precursor powder is D _Osf [nm], and the volume-based median diameter of the metal powder is D _M50 [nm], 2.28 ≦ D _M50 / _{9. The} method for producing a ceramic electronic component according to claim 7, wherein D _Osf ≦ 105.5. The method for producing a ceramic electronic component according to any one of claims 7 to 9, wherein a sintering start temperature of the metal powder is equal to or lower than a sintering start temperature of the green sheet. The method for manufacturing a ceramic electronic component according to any one of claims 7 to 10, wherein the raw material powder of the ceramic insulator contains SiO ₂ , Al ₂ O ₃ and a Ba compound.

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